A typical application of the present invention is on a bottling line where a container such as a bottle may first be rinsed, then filled, capped and labelled. Each of these processes is generally performed by a separate machine at different locations along the automated handling line. The containers are conveyed between the various machines along generally rectilinear paths and are presented to and taken from the various machines along arcuate paths where the spacing between containers is regulated to match the required spacing of the processing machine by using a star wheel and guide rail assembly.
Such a star wheel and guide rail assembly combination is described in our European Patent No. EP-B-1,663,824. Essentially, a guide rail assembly defines the outer limit of an arcuate path along which the bottles are conveyed by the star wheel. A guide rail assembly generally comprises upper and lower guide rails that support a container at two heights. As the name suggests, a star wheel is a rotating wheel of a generally star shape, the star shape being defined by a plurality of recesses that receive a container to be processed. In operation, the star wheel rotates such that the first bottle presented to the star wheel is received within a recess. The container is then conveyed along a path defined by the star wheel and the guide rail that runs around and is spaced from the centre line of the path to be fed upon exit to a processing machine. As will be appreciated, the spacing between the recesses in the star wheel determines the spacing with which containers are passed to the machine.
Any particular automated handling line is likely to process containers having a variety of different shapes and sizes. EP-B-1,663,824, referenced above, discloses both an adjustable star wheel and an adjustable guide rail. The recesses in the star wheel are adjustable to allow larger containers to be received and the guide rail may also be moved closer to and further away from the star wheel. The star wheel and guide rail may be adjusted in a co-ordinated fashion such that centreline along the path is preserved, i.e. the centre point of the containers being conveyed must be preserved, for example to allow the bottle to be filled at the same position.
JP H04 94309 discloses a segmented guide rail having upper and lower rails. The segments of each rail are attached to rods that pass through bores provided in a mounting block. The segments are driven by the rods that are constrained by the bores to move radially such that the guide rails may be moved to define arcuate paths set at different radii.